Artificial hand with worm and gear drive to thumb



April 17, 1951 M. FISHBEIN ETAL 2,549,074

ARTIFICIAL HAND WITH WORM AND GEAR DRIVE TO THUMB Filed Aug. 5, 1948 3 Sheets-Sheet 1 INVENTORS TTOENEV April 17, 1951 M. FlsHBElN ErAL ARTIFICIAL HAND WITH WORM AND GEAR DRIVE T0 THUMB Filed Aug. 5, 1948 3 Sheets-Sheet 2 Maffe Hsf/E/N, nWeE/vc'f J STEVE/vso@ INVENTORS April 17, 1951 M. FlsHBEIN ETAL ARTIFICIAL HAND WITH WORM AND GEAR DRIVE TO THUMB 3 Sheets-Sheet 3 Filed Aug. 5, 1948 INVENTORS.

Patented Apr. 17, 1951 ARTIFICIAL HAND WITH WORM AND GEAR DRIVE TO THUMB Meyer Fishhein, Los Angeles, and Lawrence J.

Stevenson,

Hawthorne, Calif.,

assignors to Northrop Aircraft, Inc., Hawthorne, Calif., a corporation of California Application August 5, 1948, Serial No. 42,606

The present invention relates generally to artiiicial hands, and one of its primary objects is to provide a hand having articulated fingers that are closed by a pull on the control cables, and which lock automatically and remain locked in any position of flexion upon relaxation of the pull.

Another object of the invention is to provide -a hand of the type described above, wherein the finger lock is released by the application of a second pull on the control cable. One of the advantages of this arrangement is that it reduces the number of controls required, and simplifies the operation of the hand.

Another object of the invention is to provide an artificial hand that is adapted to grasp articles of irregular shape and Widely varying sizes, and in which the closing force is equalized between the fingers.

Still a further object of the present invention is to provide an artificial hand having an articulated thumb that is pivoted for passive rotation between the adducted and abducted positions, and which can be locked in any one of several positions of adjustment.

Another important feature of the invention is that the thumb is likewise operatively connected to the control cables and is flexed with the fingers when the cable is pulled, so that the function of prehension is reproduced in a realistic and natural manner, enabling the amputee to grasp and hold many articles which could not otherwise be handled.

The foregoing and other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment thereof, reference being had to the accompanying drawings, wherein:

Figure 1 is a top plan view of an artificial hand embodying the principles of the invention;

Figure 2 is a partially sectioned side view of the same, taken substantially along the line 2-2 in Figure 1;

Figure 3 is a transverse sectional view, taken along the line 3 3 in Figure 2;

Figure 4 is a transverse vertical section, taken, at 4-4 in Figure 2;

Figure 5'is another transverse sectional view, taken along the line 5-5 in Figure 2;

Figure 6 is a fragmentary sectional view, taken at A6--6 in Figure 5;' 1`

-Figure '7 is another sectionalvi'ew, taken at 'l-'l in Figure 5; Y l

Figure 8 isa fragmentary elevational view of Claims. (Cl. 3--12) the shifting mechanism that operates the alternator for releasing the finger locks on alternate pulls of the control cables;

Figure 9 is a sectional view, taken at 9-9 in Figure 8;

Figure 10 is a sectional view, taken at I0-I [l in Figure 8;

Figure l1 is an enlarged sectional view, taken at H-II in Figure 1, showing details oi one of the finger locks; and

Figure 12 is an enlarged sectional view of the thumb detent, as seen along the line I2--I2 in Figure 1.

In the drawings, the hand is designated in its entirety by the reference numeral I5 and is seen to comprise a base plate I6, to which a body shell Il is attached. Mounted on the body shell I1 are articulated lingers I8, I9, 20 and 2|, thumb 22, and the actuating mechanisms therefor; the construction and operation of which will be de scribed in detail presently.

The base plate I6 constitutes the wrist of the hand and is preferably, although not necessarily, provided with a quick disconnect arrangement of the type shown and described in the pending application of Gilbert M. Motis, Serial No. 24,598,

filed May 1, 1948, now Patent Number 2,516,792

and entitled Quick Disconnect Coupling for Artiiicial Hand or Hook: to which reference may be had for full details of construction andoperation. Briefly, the base plate I6 is adapted to be coupled to a companionate member on the distal endof a forearm component F (Figure 1),*and to this end is provided on its back surface with a rearwardly projecting, vertically extending rib 23 having straight and parallel side edges which are provided with outwardly facingflanges 24. A shallow, vertically extending slot 25 (Figure 2) is milled out of the center of the rib 23, said slot being open at the bottom end and preferably closed at the top end. A circular hole 26 (Figure 5) is provided in the center of the plate I6, and slidably disposed within this hole is a connector 30 which is attached at its front end to a for'- wardly extending cable 3l. The connector 30 ex'- tends rearwardly beyond the bottoniof the slot 25 and has a radial ange 32 on the end thereof which is adapted to be received within a slot in the end of a coupling member (not shown) projecting forwardly from the face of an attach plate on the forearm member F. The said attach plate is companionate to the base plate I6, and is formed with channels to receive the flanges 24. The base plate l5 is coupled to the forearm mem,- ber by sliding the flanged rib 23 endwise intofa corresponding recess in the attach plate and then locking the parts together, for which purpose a Spring-pressed locking pin 28 is provided on the base plate adjacent the top end thereof. The pin 28 seats in a hole in the attach plate, and is adaptedto.r be unseated therefrom by a manually operable handle' 29;

As the base plate approaches its fully seated position, the connector 30 is engaged by the afore- `force for operating the fingers and thumb is transmitted to the actuating mechanismof the hand by the connector' 30, and the latter can therefore be` defined as the control'member of gauge sheet aluminum or other light metal.` The 1 Vlingers I8, (9,. 207 and: 2JI' may be of anyI desired construction and' areY herein shown as comprising flat strips 34 of beryllium copper spring tape, to which are attached inner' linger blocks 35.

The spring strips 34 are riveted at 36 to the' back of the' body shell' IIT, andi are' rein-forced at their base ends by additional spring leaves 40. The inner finger blocks 35 are' preferably formed of laminated: phenolic resiirand` are attached to the spring strips 34 at spaced intervals so as to@ give the ngers the necessary stiifnessfbetween. joints. Thefthumb and fingers', asfwell as the'm'ain body portion or the hand, may be covered with sponge rubberor` plastic f-'oamy to give the hand amore natural appearance and feel.

The fingers areheldin the normally open, or extended position byf-.the spring' tension. in strips '34,- and are closed or flexedin prhension by meansof cables 4I? whi'clf are attachedv to the tip Y end blocks 35i and extend rearwardly therefrom 'through holes in thel other blocks? toA cable drums tend to close in anatural man-ner; with a greater amount of angular deflection at the second and third joints than that obtained at the rst joint.

The cable drums 42, 43, 44 and' 45 are rotatably mounted on the bo'dy shell, I'I adjacent vthe proximal ends of the fingers, and the finger cables 4I' pass underneath and around their respective cable drums tov af point of attachment therewith. Drums Y42 andy 43, serving the forei-lnger and middle linger of the hand, are groupedtogether coaxial with one another; while drums 44 and 45, serving the third and fourth lingers, respectively,l are likewise groupedV to'- gether coaxially, but with` their common axis inclined. with respect to that of drums 42,` 43, as shown, so that thel tip ends of lingers 20 andv 2I tend to converge with the ends of ng'ers I8 and I8. This: arrangement gives a slight GUPPH? a9' tion to the hand as the fingers are closed, similar to that of the natural hand. Y

The cable drums 42, 43 are mounted on a transversely disposed tubular shaft `46 (see Figure 2) which is mounted, in turn, on a tubular center support'shaft 50. The, ends of the: tubular shaft 50 arel held. by bearing.. supports-5'I7 and 52 that are fixed to the body shell I1 adjacent its inner edge and mid-section, respectively. Cable drum 42 is xedly mounted on the outer end ofthe tubular shaft 46; while the inner end of the said shaft' has another cable drum 53 formedV integrally therewith'. The other linger cable drum 431' isformedf. as: an integral part of a sleeve 54 at on'ef' end thereof; said sleeve encircling the tub'ular shaft 46 between the hub portions of the drums 47.2, 53-andbeing free to turn on the shaft. Also integral with the drum 43 is another cable 'drum 55;-, the function of which is to drive the drum 43. The sleeve 54 is slotted longitudinally from theend opposite drumsl 43,. 55,which makes it possible for the sleeve to be constricted against the tubular shaft 46, for reasons that Will bel explained hereinafter. 1.

The two finger cable drums 44 and l45 are likewise mountedv on a center support shaft (not shown) which is held at its ends by the center support 52 and by anotherv bearing. support` 55 spaced laterally therefrom. Drum-"44 has another drum 56 formed integrally therewith and bothof these are mounted rigidly on one end of a` tubular shaft (notv shown) which is journalled 'onthe aforesaid' center support shaft. Encircling the said tubular shaft and free to turniV thereon is all sleeve 60' which is slottedl longitudinally from oneenclin the 'same manner as sleeve 54, so that it? too can bel constricte'd about its tubularsha'ft. The finger cable drum 45?y and. another drum 6I are form-ed integrally withthe sleevef filll on the outer end thereof.

As-Iviewed in Figure 2, the fingers are closedV by the counterclockwise rotation of cable drums 421,- 43, 44'5 and 45, and one of the features of the inventionlis the provision of locking means operable to lock the lingers in flexed position when the linger-closing force on the control member is relaxed; The locking means, in this' case; consists of twov self-'energizing locks 62 and 62' which encircle and engage the Slotted sleeves 541 and 60,', respectively. The two locks are identical in construction, andV each comprises a brakeband 63ancircling its respective sleeve, and an anchorv link 64, one end of which is securedbya screw E5 to a block 66 on the body shell I'I. The two ends of the @band 63 are connected to the anchorlink' 64 by pins I0 andi 7| which are spaced apart in a generally radial direction, as shown'in Figure 1l'. Theband 63 is normally adjusted to drag lightly on the sleeve 54, and offers' little orno resistanceY to counterclockwise rotation of the latter, which is the direction of rotation of the cable drums to close the fingers.` When Ythe finger-closing force onV theA cable drums is relaxed', however, the fingers tend to straighten out to the extended position, either by reason of the load carried by the fingers or due to the Yspring tension of strip `muscular effort on the control cable. .62, 62' are adapted to be released simultaneously annular flange 33.

`3| is trained and then attached thereto.

from turning with respect to the sleeve. Thus,

both of the finger cable drums of each group are restrained by the locks 62, 62' against turning in the direction to open the nngers, and the fmgers can therefore be kept locked in the flexed condition to enable the amputee to carry a load with the articial hand without exerting a sustained The locks responsive to the next successive application of `force to the control member 30 following the relaxation of the finger-closing force; said lockreleasing action being effected through the agency of actuating means, designated generally at '|2, which will presently be described in detail.

The finger cable drums 42, 43, 44 and 45 are driven by means of cables 'I5 which are trained around and attached to the drums 53, 55, 56 and 6|. The cables I5 converge rearwardly from their respective drums through guide blocks 16 and and are attached in any suitable manner to a wide drum 18 at the rear end of the hand. As

best shown in Figure 4, the drum 'I8 is mounted on a transverse shaft 79, and is secured thereto by a pin 80. The shaft 'I9 is journalled at one end in a bushing 8| mounted in a support 82 which is fastened to the inside surface of the A bevel gear 83 is formed on the other end of the shaft l0, and a central bore 84 is drilled into the end of the shaft on the axis thereof to form a journal for a short pilot shaft 85 which is mounted in and projects from a support member 36; said support member being attached to the inside of flange 33 across from support 62.

A. drive pin ring B1 is mounted on the shaft 70 alongside the bearing support 82, and is secured to the shaft to rotate therewith by means of a pin y00. The ring 8l has three equally spaced holes 9| formed therein, only one of which can be seen in Figure 4. Drive pins 02 are pressed into the holes 9|, and these extend parallel to the shaft 'I0 to the drum I8, where theyare received within holes 63.

Mounted on the shaft 'I9 alongside the drum 'I8 is a main drive wheel 04 which is in the form of a cable drum, around which the control cable main drive wheel 04 is slidable axially along the shaft 10 and has a limited amount of lost motion rotation with respect thereto. The lost motion of the wheel 04 relative to shaft 'I0 is limited to of rotation, and is obtained by providing three circumferentially extending slots 9'I in the wheel, through which the drive pins 92 pass. The wheel 04 is thus free to turn on the shaft 'I9 until the pins 92 engage one end or the other of slots `01; after which the wheel and shaft are constrained to rotate together. The purpose of this lost motion arrangement is to operate the lock-release mechanism l2, as will be explained sh-ortly.

From the foregoing description, it will be seen that the control member and cable 3| cause the main drive wheel 94 to rotate when a pull is applied to the control cable. Wheel 04 turns on the shaft 19 in the direction of the arrow in Figure 9 until the ends of slots 0T engage the pins 92., after which the wheel drives the shaft with its attached cable drum '|8.` As the drum 'I8 revolves, the cables l5 are pulled rearwardly, driving the linger cable drums 42, 43, 44, and 45, and thereby pulling the fingers closed. When the pull on the control cable is relaxed the locks 62 and 62 tighten up on their respective cable The Y IIO, (see Figure 6).

- 6 drums, as described earlier,`leaving the fingers locked in the flexed condition.

The alternator mechanism 'I2 for releasing the locks 62, 62 on the next succeeding application of force to the control member 30 includes an alternator wheel |00 and a ratchet wheel IUI, both of which are mounted on a short stud shaft |02 projecting from a boss |63 on the support member 86. The ratchet wheel |0| is fixedly attached to the alternator wheel |00, and the two wheels rotate as one on the shaft |02. The alternatorwheel |00 is provided on its periphery with angularly spaced, alternate high and low cam portions |04 and |05, respectively, which are successively engaged by a pin |06 on a follower The follower ||0 is pivoted at I on a bracket I2 projecting forwardly from the surface of base plate I6, and one end. thereof is bifurcated so as to straddle the alternator wheel |00; the pin |66 extending transversely across the slot in the bifurcated end. The other end of the follower II 0 is slotted or drilled to receive the rear end of a wire rod I I3 which extends forwardly therefrom through a slot in an angle bracket |I4, and terminates at its front end in a transversely disposed triangular yoke frame I5, The yoke frame II 5 is made of brass wire, silver soldered at the joints, and fastened to the opposite ends thereof are two forwardly extending cables ||6 which are engaged on hooks |20 provided on the bottom sides of the brake bands 63 of the locks 62, 62. When the cables ||6 are pulled rearwardly, the brake bands 63 are pulled around very slightly in a counterclockwise direction (Figure ll), which releases the locks and frees the finger drums, allowing the fingers to extend by the spring tension of the strips 34. In order that the brake bands 63 may be free to rotate the slight amount necessary to release the lock, the anchor link 64 is fastened rather loosely to the block 66 by screw 65, and is therefore able to rock, or give slightly under the p-ull of the cable II6.

The lock-releasing pull on cables I I6 is applied by a compression spring I2I (Figure 6) which en- Vcircles the yoke wire II3 and bears at one end against the lower arm of the pivoted follower I I0; the other end of the spring abutting against the bracket |I4. The spring I2I pushes rearwardly against the lower end of the follower, which causes the pin |06 at the top end thereof `to bear against the periphery of the alternator wheel |00. When the pin |06 is engaged by one of the high cam portions |04, as shown in Figure 6, the spring |2| is compressed and the lock yoke wire ||3 is relieved of tension. As the alternator wheel turns to the next position, wherein one of the low cam portions |05 is registered with the pin |06, the spring |2| rocks the follower |I0 in a clockwise direction to cause the pin |06 to follow the periphery of the alternator )wheel down into engagement with the low cam portion. This rocking movement of the follower |I0 causes the lower arm thereof to move to the left, carrying the lock yoke wire I I3 with it, and thereby exerting the lock-releasing pull on cables II6.

Rotation of the alternator wheel |00 to bring the high and low cam portions |04, |05 successively into engagement with the follower pin |06 is effected by means of a bell crank shifter |22 which is pivoted at |23 on a support |24 projecting from the base plate |6. One arm of the bell crank |22 is provided with a hook |25 which is engageable with the teeth of ratchet wheel 0l to advance the latter by an angular distance equal to the spacing between two adjacent teeth each time the bell crank is rocked on its pivot. It might be mentioned at thispoint that the ratchet wheel has the same number of teeth as the alternator wheel |00 has cam portions |04 and |05, and therefore advancement of the ratchet wheel by one tooth causes the alternator wheel to advance from one cam portion to the other, i. e., from high to low, or Vice versa.

The other arm of the bell crank has a rider |26 provided thereon which is shaped to t within a circumferential groove |30 in a throw-out ring I3 I. The throw-out ring |3| is slidably mounted on the shaft 'I9 and is constrained to rotate therewith by the drive pins 92 which extend through holes |32 in the ring. One end of the throw-out ring |3| is engaged by a compression spring |33 which urges the ring toward the main drive wheel 04; said spring encircling the drive pin ring 8l and bearing against a radial flange |34 provided thereon.

The throw-out ring |3| is shifted axially along the shaft 19 responsive to the 20 of lost motion rotation of the main drive wheel 94 relative to the shaft, and this is`accomplished by means of cooperating cam protuberances provided on the adjoining faces of the members 94 and |3|. The cam protuberances on the main drive wheel 94 are designated by the reference numeral |35, and are preferably cone-shaped; While those on the throw-out rin-g, indicated at |35, are spherically rounded. Both sets of cam protuberances |35 and |36 may conveniently be produced by pressing rivets |3'| with suitably shaped heads'into holes in the members 94 and ISI, as shown in Figure 4.

Spherical depressions |40 are formed in the sides of the throw-out ring |3| immediately alongside the spherical cam protuberances |36, and these depressions are adapted to receive the conical cam protuberances |35 when the main drive wheel 94 is at one end of its lost motion travel. This arrangement permits theV throwout ring |3| to move closer to the main drive wheel 94 than would otherwise be possible, and thereby increases the extent of axial displacement of the throw-out ring |3| along the shaft 19 when the cam protuberances are riding one on top of the other, as in Figure 8. Thus, during the initial rotation of the main drive Wheel 94, the cone-shaped cam protub'erances |35 climb up out of the depressions |40 and onto the the tops of cam protuberances |35 on the throwout ring I3 I shifting the latter to the right (Figure 8) against the pressure of spring |33. This axial movement of the throw-out ring causes the shifter bell crank |22 to rock on its pivot |23, thereby advancing the ratchet Wheel |0| by one tooth and carrying the alternator wheel |00 along with it. As mentioned earlier, the progressive advancement of the alternator wheel |00 causes rst one and then the other of cam portions |04 and |05 to engage pin |06 on the follower'll, and thereby actuate the lock-release mechanism on alternate pulls of the control cable. Y

The thumb 22 is mounted on the body shell l1 for bothiiexion-extension and abduction-adduction movements, and to this end a U-shaped thumb yoke |42 is supported near the ends of its arms for swinging movement about an ab- 8 4 A |42 are drilled and bushed to receive a tubular shaft |43 (Figure 3) which is journalled at its ends in spaced bearing supports |44 andV |45, the later being formed integrally with the bearing support 05 for the drive shaft |9. rIfhe bight portion or the yoke |42 is slotted out to receive the base of thumb 22, and the latter is connected to the yoke by a tubular pivot shaft |46. The axis of the shaft |46 represents the flexionextension axis of the thumb, and swinging movementof the latter about said axis is defined as flexion when the thumb moves toward the fingers, and as extension when the movement is away from the'ngers.

The thumb 22 is adapted to be swung to any one of three positions about the abduction-adduction axis, as shown at A, B, and C in Figure 3, and is locked inthe selected position by means of a spring-pressed plunger |50 mounted on bearing support |44, which is engageable with any one of three recessed seat cavities |5| in a flange |52, projecting radially from the yoke |42 at one end thereof. The plunger |50 is slidably disposed with the bore |49 (Figure 12) ofa cylindrical housing |53 that is mounted on a web portion of the bearing support |44, and bearing against the end of the plunger is a spring r|54 which is backed up by a plug r|55 closing the end of the housing bore. The seating engagement of the spring pressed detent |50 with the depressions |5I in the yoke provides aV yieldable lock for holding the thumb in any one of its three positions, and to change its position, the thumb is forced around so as to overcome the spring y 35' vforce on the d etent.

The thumb is ilexed simultaneously With the ngers by the action of the control member 30, and to this end a driving connection is provided between the drive shaft 'i9 and the thumb; said driving connection being in the form of a bevel gear which is xed to the shaft |43 in mesh with the bevel gear 83 on shaft le. Also xedly mounted on the shaft |43 between the arms of yoke |42 is a worm |6I which meshes with a worm gear sector |52 fixed to the base of thumb 22 concentric with the axis of shaft |46. In the illustrative embodiment, the base of thumb 22 has been slotted out, and womi gear sector |62 is inserted into the slot and secured in place by pins (not shown) The worm and gear drive to the thumb is irreversible in nature, and the thumb is thus locked against displacement by the action of external forces.

The operation of the thumb is believed to be self-evident from the foregoing description. Rotation of the drive shaft 'I0 responsive to a pull on the control member 30 causes the bevel gear 83 to drive its companionate gear |60 and thereby rotate the worm |6|. Worm IBI, in turn, drives Worm gear sector |02, which causes the thumb 22 to swing in toward the fingers, about the shaft |45. Since the driving force for flexing the thumb about axis |46 is transmitted along the abduction-adduction axis, exion movement of the thumb is not appreciably affected by the position of the thumb about the said axis.

While We have shown and described in considerable detail What we believe to be the preferred form of our invention, it is to be understood that such details are not restrictive, and that various changes may be made in the shape and arrangement of the Vseveral parts WithoutV departing from thebroad scope ofthe invention, as dened in the appended claims.

asiaou.

9 .We claim:

1. In an artificial hand, the combination of a plurality of articulated fingers that are springbiased toward the open position. a rotatable member journaled on said hand adjacent the proximal ends of said fingers, tension-transmitting means connecting said member to at least one of said fingers, whereby the latter is pulled closed when said member is rotated in one direction, a force-transmitting control member connected to said rotatable member so as to rotate the latter in said one direction when a force is applied to the control member, a selfenergizing releasable friction lock engageable with said rotatable member to hold the same against rotation in the finger-opening direction when the finger-closing force on said control member is relaxed, a rotatable alternator wheel journaled on said hand and having alternate high and low cam portions provided thereon, a follower engaging' said cam portions and connected to said lock, said follower being inoperative when engaged by one of said cam portions, and operable to release the lock when engaged by the other cam portion, and means operable by'successive applications of force on said control member for progressively advancing said alternator wheel so that said follower is alternately engaged by said high and low cam portions.

2. In an artiiicial hand, the combination of a plurality of articulated fingers, a rotatable member journaled on said hand adjacent the proximal ends of said fingers, tension-transmitting means connecting said member to at least one of said fingers, whereby the latter is pulled closed when said member is rotated in one direction, a rotatable drive shaft connected to said rotatable member to drive the latter, a wheel mounted on said drive shaft for a limited amount of rotation with respect thereto, a control member connected to said wheel to rotate .the same when a force is applied to the control member, releasable locking means frictionally engageable with said rotatable member to hold the same against rotation in the fingeropening direction when the finger-closing force on said control member is relaxed, and means actuated by the rotation of said wheel relative to said drive shaft for releasing said locking means upon application of the next succeeding force to said control member following the finger-closing force.

3. In an artificial hand, the combination of a plurality of articulated fingers, a rotatable member journaled on said hand adjacent the proximal ends of said fingers, tension-transmitting means connecting said member to at least one of said fingers, whereby the latter is pulled closed when said member is rotated in one direction, a rotatable drive shaft connected to said 4rotatable member to drive the latter, a wheel mounted on said drive shaft for a limited amount of rotation with respect thereto, a control member connected to said wheel to rotate the same when a force is applied to the control member, releasable locking means frictionally engageable with said rotatable member to hold the same against rotation in one direction when the linger-closing force on said control member is relaxed, a rotatable alternatorwheel journaled on said hand and having alternate high and low cam portions provided thereon, a follower engaging said cam portions and connected to said locking means, said follower being inoperative when engaged by one of said cam portions, and operable to release said. locking means when engaged by the other cam portion, and means responsive to rotation of said wheel relative to said drive shaft for progressively advancing said alternator wheel so that said follower is alternately engaged by said high and low cam portions.

4. In an artificial hand, the combination of a plurality of articulated lingers, a rotatable member journaled on said hand adjacent the proximal ends of said lingers, tension-transmitting means connecting said member to at least one of said fingers, whereby the latter is pulled closed when said member is rotated in one direction, a rotatable drive shaft connected to said rotatable member to drive the latter, a main drive wheel mounted on said drive shaft for a limited amount of rotation relative thereto, a control member connected to said main drive wheel to rotate the same when a force is applied to the control member, a throw-out wheel slidably mounted on said drive shaft and non-rotatable with respect thereto, cooperating means on said main drive wheel.

and said throw-out wheel, whereby the latter is shifted axially on said drive shaft responsive to the limited rotation of the main drive wheel relative to the drive shaft, locking means engageable with said rotatable member to hold the same against rotation in one direction when thengerclosing force on said control member is relaxed and means operable by said axial shifting movement of said throw-out wheel to release said.

locking means and allow said fingers to open.

5. In an articial hand, the combination of a plurality of articulated lingers, a rotatable member journaled on said hand adjacent the proxi` mal ends of said fingers, tension-transmitting means connecting said member to at least one of said ngers, whereby the latter is pulled closed when said member is rotated in one direction, a` rotatable drive shaft connected to said rotatable member to drive the latter, a main drive wheel mounted on said drive shaft for a limited amount` of rotation relative thereto, a control member connected to said main drive wheel to drive the: same when a force is applied to the control member, a throw-out wheel slidably mounted on said drive shaft and non-rotatable with respect `thereto, cooperating means on said main drive wheel and saidthrow-out wheel, whereby the .latter is shifted axially on said drive shaft responsive to the limited rotation of the main drive wheel relative to the drive shaft, a self-energizing lock engageable with said rotatable member to hold the same against turning in one direction when the linger-closing force on said control member is relaxed, a rotatable alternator wheel journaled on said hand and having alternate high and low cam portions provided thereon, a follower engaging said cam portions and operatively connected to said locking means, said follower being operable to release said lock when engaged by one of said cam portions, and means responsive to the axial shifting movement of said throw-out wheel for progressively advancing said alternator wheel so that said follower is alternately engaged by said high and low cam portions.

6. In an artificial hand, the combination of a plurality of articulated lingers, a rotatable member journaled on said hand adjacent the proximal ends of said fingers, tension-transmitting means connecting said member to at least one of said fingers, whereby the latter is pulled closed 76 when said member is rotated in one direction, a

Y l Il rotatable drive shaft connected to said rotatable member to drive the latter, a main drive Wheel mounted on said drive shaft for a limited amount of rotation relative thereto, a control member connected to said main drive wheel to drive the same when a forcey is applied to the control member, a throw-out wheel slidably mounted on said drive shaft and non-rotatable with respect thereto, cooperating means of said main drive wheel and said throw-out Wheel, whereby the latter is shifted axially on saidr drive shaft responsive to the limited rotation of the main drive wheel relatveto the drive shaft, a self-energizing lool; engageable with said rotatable member toV hold thesaine against turning in one direction when the finger-closing force on said control member is relaxed, a rotatable alternator wheel journaled on said hand and having alternate high and' low cam portionsl provided thereon, a follower engaging* said cam portions andl operatively connected tofsaid locking means, said follower being operablev to release said lock when engaged by oneA of said cam portions, a ratchet wheel fixed tosaid alternator Wheel, and a bellf crank pivotedon said hand for rocking movement about an axis perpendicular to the axes ofsaidA ratchet'wheel 'and for closing saidngers comprising aI cable drumV` for each of saidA fingers, said druinsj beingA independently rotatable and arranged in coaxial' groups of two adjacent the proximal, ends ofl said' ngers,ja cable attached to each of said' drums and extending forwardly therefrom along its frespective finger to"V a point ofv attachment with, the latter, said cables being.0 operative toV pulllsaidngers closed when saidcable drums. areurotatedin one direction, apair of self-energizing locks, each of said locks, beingengageabie with both drums in oneof,said'groupsof twoto lock4 the. same againstA rotation in` the ngeropening direction, arotatable drive. shaft oon-` nected to each of'said cable drumsto drive the same, a main drive. wheelk mounted on said drive shaft forv a limited amountA ofrotation with respect thereto, a controlmembereconnected to said drive wheel to rotate the same Whena. force is applied to the, control member, and! means actuated by therotation ofsaid wheel relative to said. drive shaft for simultaneously. releasing both of said locks upon application of;A the next-,succeeding force to said control member. following` theV finger-closinglforce, whereby; said fingers. are released andallowed ltoppen.,`

8. Inan articial hand, ,the combination .of a, plurality of articulated ngersihat are springbiased toward the open position,actuating means. for closing said fingers ,comprisinga cable drum for each o f the lingers, saidldrums, being independently rotatable and arranged in coaxial: groups of two adjacent the proximalends of said fingers, Ja cable attached to` each4 of vsaiddrunrs and" extending; forwardla therefromY alone f its; respective :linger `to :a ,point Aof attachment with' the latter, said `cables being operative to pulli'said Vdrive wheel mounted on said drive shaft for a limited amount of rotation with respect thereto, a control member connected to said main' drive wheel to drive the same when a force' is applied to the control member, a throw-out Wheel slidably mounted on said drive shaft andnon-rotate able with respect thereto, cooperating cam means on said main drive Wheel and said throw-out wheel, Iwhereby the latter is shifted axially on said drive shaft responsive' to the limited' rotation of the main drive wheel relative to the drive shaft, a rotatable alternator wheel journaled on said hand Vand having alternate high and lovv cam portions provided thereon, a-spring-pressedv follower engaging said cani portions, ,a yoke connecting said follower to both of said locks, wherebythe latter are released when the follower is engaged by'one of said cam portions, a ratchet wheel xed to said alternator wheel, anda belll crank` pivote'd on said hand for rocking inov'ement about an axis perpendicular to the ax'esfof` said ratchet wheel and said throw-out wheel, omel arm of said bell' crank beingl en'gageablen with said,` ratchet'. wheel to advance tli'e same v'vheri the bell crank isrockedlsoth'at' sa'idfolloweri's alternately' engaged by said high' and'low cam portions on said' alternator wheel, andthe o'tlie'r-`Y armv of said'` bell crank being engaged." by,Y said each time saidthrow-outiwheel is shifte'd'axiallyn along said drive shaft'. s

9i In an* artificial hand, the combination of" supporting" means, ayoke pivotedo'ri said? suppivoted: on said' yoke for exionlan'd' extension' movement; a: force-transmitting control `member,'

and meansy connecting said control member' to saidtliumb, whereby the latter is flexed responsiveto the application'ofa force'to the control member.

10,. In an artificial hand, the` combnationfof arbody. shell, a pair of spacedsupportsxed-to said"sheil,.a yokepivoted'ori said supportsgfor rotation'about'the' abduction-adduction axis ofy the thumb; a thumb" pivcted on said yoke-fori swinging movement about aV flexion-extension axis, a gear' fixed tfo said -thumb coaxial with said flexion-extension axis," another gear interlrneshed with,- saidn firstnamed gear, andV journalld frrotation abouti said abduction-adduction axis, andv a' control member" connected tof saidflastnam'edlgear to drive the latter, whereby'. saidf thumb' is flexed 'responsive tothe application, of a Aforce tosaid control member'.

ll'. Iffrranjarticial ha'n'd the' combination of "a' body: shell, a; pair .of 4spacedsupports'fixed td saidshel'lj, a Ll-sh'apedlyokje having arms,V pivotd 'on saidfsupports forl rotation about the abductionadduotion'axis of .th'jejthumo althumb pivoted onl th e'b i'gh`tofsaid U-'shaped yoke for swinging; movement about a` exion-.extension axis', awormg disposed between the, arms of saidyokeandjournailed for rotation aboutisaid abduction-adduc- 13 tion axis, a worm gear sector fixed to said thumb concentric with said flexion-extension axis and meshed with said worm, a control member, and means actuated by said control member for rotating said worm to drive said worm gear sector and thereby iiex said thumb.

12. In an artificial hand, the combination of a body shell, a pair of spaced supports fixed to said shell, a yoke pivoted on said supports for rotation about the abduction-adduction axis of the thumb, a thumb pivoted on said yoke for swinging movement about a flexion-extension axis, a spring-pressed detent on one of said supports engageable with said yoke to hold the same in any one of several angularly spaced positions about said abduction-adduction axis, a forcetransmitting control member, and means connecting said control member to said thumb, whereby the latter is swung about said flexionextension axis responsive to the application ci force to the control member.

13. In an articial hand, the combination of a body shell, a pair of spaced supports xed to said shell, a U-shaped yoke having arms pivoted on said supports for rotation about the abductionadduction axis of the thumb, a thumb pivoted on the bight of said U-shaped yoke. for swinging movement about a flexion-extension axis, a spring-pressed detent on one of said supports enn gageable with said yoke to hold the same in any one of several angularly spaced positions about said abductioneadduction axis, a worm disposed between the arms of said yoke and journalled for rotation about said abduction-adduction axis, a worm gear sector fixed to said thumb concentric with said flexion-extension axis, a rotatable main drive wheel, a control member connected to said wheel so as to rotate the latter when a force is applied to the control member, and a driving connection between said wheel and said worm, whereby said thumb is swung about said iiexionextension axis responsive to the application of force to said control member.

14. In an artiiicial hand having a body shell, a plurality of articulated fingers, and a thumb, the combination of: a rotatable member adjacent the proximal ends of said fingers, tension transmitting means connecting said member to at least one of said ngers, whereby the latter is pulled closed when said member is rotated in one direction, a rotatable drive shaft connected to said rotatable member to drive the latter, a wheel mounted on said drive shaft for a limited amount of rotation with respect thereto, a control member connected to said wheel to rotate the same, locking means engageable with said rotatable member to hold the same against rotation in the iinger-opening direction when the ringer-closing force on said control member is relaxed, an actuating member connected to said locking means and operable to release the latter on alternate applications oi force to said control member, a pair oi spaced supports xed to Said shell, a yoke pivoted on said supports for rotation about the abduction-adduction axis of the thumb, said thumb being pivoted on said yoke for swinging movement about a f1exion-extensicn axis, and means, including an irreversible gear, connecting said drive shaft to said thumb, whereby the latter is swung about said flexion-extension axis responsive to the application of force to the control member.

15. In an artiilcial hand having a body shell, a plurality of articulated iingers, and a thumb, the combination of a cable drum for each of said fingers, said drums being independently rotatable and arranged in coaxial groups of two adjacent the proximal ends of said fingers, a cable attached to each of said drums and extending forwardly therefrom along its respective iinger to a point f of attachment with the latter, said cables being operative to pull said lingers closed when said cable drums are rotated in one direction, a pair of self-energizing locks, each of said locks being engageable with both drums in one of said groups of two, to lock the same against rotation in the linger-opening direction, a rotatable drive shaft connected to each of said cable drums to drive the latter, a main drive wheel mounted on said drive shaft for a limited amount of rotation with respect thereto, a control member connected to said drive wheel to rotate the same when a force is applied to the control member, means actuated by the rotation of said wheel relative to said drive shaft for simultan-eously releasing both of said locks upon application of the next succeeding force to said control member following the nger-closing force, whereby said lingers are released and aliowed to open, a pair of spaced supports iixed to said shell, a U-shaped yoke having arms pivoted on said supports for rotation about the abduction-adduction axis of the thumb, said thumb being pivoted on the bight of said U- shaped yoke for swinging movement about a iiexion-extension axis, a worm disposed between the arms of said yoke and journalled for rotation about said abduction-adduction axis, a Worm gear sector xed to said thumb concentric with said exion-extension axis and meshing with said Worm, and a pair of intermeshing gears connecting said drive shaft with said worm, whereby the latter is driven to flex said thumb responsive to the application of a ringer-closing force on said control member.

MEYER FISHBEIN. LAWRENCE J. STEVENSON.

EITED The following references are of record in the file ci this patent:

UNITED STATES PATENTS Number Name Date 984,179 Aydt Feb. 14, 1911 1,253,823 Hobbs Jan., 15, 1918` 1,324,564 Pringle Dec. 9, 1919 1,402,476 Carnes Jan. 3, 1922 1,507,682 Pecorella et al Sept. 9, 1924 FOREIGN PATENTSV Number Country Date 399,490 Germany July 23, 1924 

